Detection of antibodies against SARS-Coronavirus using recombinant truncated nucleocapsid proteins by ELISA.
Severe acute respiratory syndrome (SARS) is a lifethreatening emerging respiratory disease caused by the coronavirus, SARS-CoV. The nucleocapsid (N) protein of SARS-CoV is highly antigenic and may be a suitable candidate for diagnostic applications. We constructed truncated recombinant N proteins (N1 [1-422 aa], N2 [1- 109 aa], and N3 [110-422 aa]) and determined their antigenicity by Western blotting using convalescent SARS serum. The recombinants containing N1 and N3 reacted with convalescent SARS serum in Western blotting. However, the recombinant with N2 did not. In ELISA using N1 or N3 as the antigens, positive results were observed in 10 of 10 (100%) SARS-CoV-positive human sera. None of 50 healthy sera gave positive results in either assay. These data indicate that the ELISA using N1 or N3 has high sensitivity and specificity. These results suggest that the middle or C-terminal region of the SARS N protein is important for eliciting antibodies against SARS-CoV during the immune response, and ELISA reactions using N1 or N3 may be a valuable tool for SARS diagnosis.
Lee
Hyun-Kyoung
HK
Department of Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea.
Lee
Byoung-Hee
BH
Dutta
Noton Kumar
NK
Seok
Seung-Hyeok
SH
Baek
Min-Won
MW
Lee
Hui-Young
HY
Kim
Dong-Jae
DJ
Na
Yi-Rang
YR
Noh
Kyoung-Jin
KJ
Park
Sung-Hoon
SH
Kariwa
Hiroaki
H
Nakauchi
Mina
M
Mai
Le Quynh
le Q
Heo
Suk-Jin
SJ
Park
Jae-Hak
JH
D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D015870:Gene Expression; D006801:Humans; D019251:Nucleocapsid / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D045169:Severe Acute Respiratory Syndrome / Q000175:diagnosis / Q000276:immunology*
D000914:Antibodies, Viral; D000956:Antigens, Viral; D011994:Recombinant Proteins